Radiations of various forms such as X-Rays, gamma-Rays, UV-Rays, laser light, microwaves, electron beams as well as particle beams of, for example neutrons, and protons, have been used to treat cancer related issues. Some of said radiations have been used in such applications, in combination with radiation sensitive molecules. Electromagnetic and ionizing radiations are indeed capable of breaking the DNA molecule of the cell, thereby preventing said cell from growing and dividing. This effect is mainly due to damages created by electrons and/or high energy photons (energy higher than 2 KeV) emitted after ionization.
The term “Ionizing radiations” refers to highly-energetic particles or waves that can detach (ionize) at least one electron from an atom or molecule. Ionizing ability depends on the energy of individual particles or waves, and not on their number. A large flood of particles or waves will not, in the most-common situations, cause ionization if the individual particles or waves are insufficiently energetic.
Examples of ionizing radiations are energetic beta particles, photons, neutrons, electron and alpha particles. The ability of light waves (photons) to ionize an atom or molecule varies across the electromagnetic spectrum. X-Rays and gamma-Rays will ionize almost any molecule or atom; far ultraviolet light will ionize many atoms and molecules; near ultraviolet and visible light are ionizing very few molecules; microwaves and radio waves are non-ionizing radiations.
WO 2005/120590 describes a particle comprising (i) a nucleus comprising a first inorganic compound absorbing X-Rays and emitting UV-visible energy, and (ii) a second, inorganic or organic compound, absorbing UV-visible energy and producing free radicals on contact with water or oxygen. The activated particles convert the surrounding oxygen to free radicals which are highly reactive species producing irreversible damage in cells.
US 2007/0274909 relates to nanoparticles for use in imaging or in radiation treatment of biological material, comprising a VUV or UV-C emitting material which absorbs high energy radiation and emits VUV or UV-C radiation. The VUV or UV-C emitting materials described in this specification are intentionally or non-intentionally, but systematically, doped with an activator the aim of which is to allow the described VUV or UV-C radiation emission. Doping agents may however be associated with an increased toxicity depending on their localization in the particle or on their solubility in the dispersion medium.
U.S. Pat. No. 6,955,639 describes a method of enhancing X-Rays radiation effects using metal, in particular gold, nanoparticles.
Inventors herein provide new and powerful nanoparticles, which are easier and cheaper to prepare than those described in the art, but more importantly and surprisingly able to achieve a very efficient alteration or destruction of target cells in combination with ionizing radiations, as herein demonstrated.
Another feature exhibited by the herein described nanoparticles is their ability to remain inside the tumor for several days allowing reducing the number of nanoparticles and/or nanoparticles aggregates injections to a minimum, in the context of a complete radiotherapy treatment.